7 files changed, 142 insertions, 13 deletions

diff --git a/crates/ra_ide/src/display/short_label.rs b/crates/ra_ide/src/display/short_label.rs
index 0fdf8e9a5..b5ff9fa2d 100644
--- a/crates/ra_ide/src/display/short_label.rs
+++ b/crates/ra_ide/src/display/short_label.rs
@@ -47,6 +47,12 @@ impl ShortLabel for ast::Module {
     }
 }
 
+impl ShortLabel for ast::SourceFile {
+    fn short_label(&self) -> Option<String> {
+        None
+    }
+}
+
 impl ShortLabel for ast::TypeAlias {
     fn short_label(&self) -> Option<String> {
         short_label_from_node(self, "type ")
diff --git a/crates/ra_ide/src/goto_definition.rs b/crates/ra_ide/src/goto_definition.rs
index 4e3f428fa..b44b6fe22 100644
--- a/crates/ra_ide/src/goto_definition.rs
+++ b/crates/ra_ide/src/goto_definition.rs
@@ -1,6 +1,6 @@
 use hir::Semantics;
 use ra_ide_db::{
-    defs::{classify_name, classify_name_ref, NameClass},
+    defs::{classify_name, classify_name_ref},
     symbol_index, RootDatabase,
 };
 use ra_syntax::{
@@ -40,10 +40,7 @@ pub(crate) fn goto_definition(
                 reference_definition(&sema, &name_ref).to_vec()
             },
             ast::Name(name) => {
-                let def = match classify_name(&sema, &name)? {
-                    NameClass::Definition(def) | NameClass::ConstReference(def) => def,
-                    NameClass::FieldShorthand { local: _, field } => field,
-                };
+                let def = classify_name(&sema, &name)?.definition(sema.db)?;
                 let nav = def.try_to_nav(sema.db)?;
                 vec![nav]
             },
@@ -85,9 +82,7 @@ pub(crate) fn reference_definition(
     name_ref: &ast::NameRef,
 ) -> ReferenceResult {
     let name_kind = classify_name_ref(sema, name_ref);
-    if let Some(def) = name_kind {
-        let def = def.definition();
-
+    if let Some(def) = name_kind.and_then(|def| def.definition(sema.db)) {
         return match def.try_to_nav(sema.db) {
             Some(nav) => ReferenceResult::Exact(nav),
             None => ReferenceResult::Approximate(Vec::new()),
@@ -134,6 +129,32 @@ mod tests {
     }
 
     #[test]
+    fn goto_def_for_extern_crate() {
+        check(
+            r#"
+            //- /main.rs
+            extern crate std<|>;
+            //- /std/lib.rs
+            // empty
+            //^ file
+            "#,
+        )
+    }
+
+    #[test]
+    fn goto_def_for_renamed_extern_crate() {
+        check(
+            r#"
+            //- /main.rs
+            extern crate std as abc<|>;
+            //- /std/lib.rs
+            // empty
+            //^ file
+            "#,
+        )
+    }
+
+    #[test]
     fn goto_def_in_items() {
         check(
             r#"
diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index aa48cb412..a632ea6a2 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -85,8 +85,8 @@ pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeIn
     let node = token.parent();
     let definition = match_ast! {
         match node {
-            ast::NameRef(name_ref) => classify_name_ref(&sema, &name_ref).map(|d| d.definition()),
-            ast::Name(name) => classify_name(&sema, &name).map(|d| d.definition()),
+            ast::NameRef(name_ref) => classify_name_ref(&sema, &name_ref).and_then(|d| d.definition(sema.db)),
+            ast::Name(name) => classify_name(&sema, &name).and_then(|d| d.definition(sema.db)),
             _ => None,
         }
     };
@@ -304,7 +304,10 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
                     let docs = Documentation::from_ast(&it).map(Into::into);
                     hover_markup(docs, it.short_label(), mod_path)
                 }
-                _ => None,
+                ModuleSource::SourceFile(it) => {
+                    let docs = Documentation::from_ast(&it).map(Into::into);
+                    hover_markup(docs, it.short_label(), mod_path)
+                }
             },
             ModuleDef::Function(it) => from_def_source(db, it, mod_path),
             ModuleDef::Adt(Adt::Struct(it)) => from_def_source(db, it, mod_path),
@@ -1107,6 +1110,46 @@ fn bar() { fo<|>o(); }
     }
 
     #[test]
+    fn test_hover_extern_crate() {
+        check(
+            r#"
+//- /main.rs
+extern crate st<|>d;
+//- /std/lib.rs
+//! Standard library for this test
+//!
+//! Printed?
+//! abc123
+            "#,
+            expect![[r#"
+            *std*
+            Standard library for this test
+
+            Printed?
+            abc123
+            "#]],
+        );
+        check(
+            r#"
+//- /main.rs
+extern crate std as ab<|>c;
+//- /std/lib.rs
+//! Standard library for this test
+//!
+//! Printed?
+//! abc123
+            "#,
+            expect![[r#"
+            *abc*
+            Standard library for this test
+
+            Printed?
+            abc123
+            "#]],
+        );
+    }
+
+    #[test]
     fn test_hover_mod_with_same_name_as_function() {
         check(
             r#"
diff --git a/crates/ra_ide/src/references.rs b/crates/ra_ide/src/references.rs
index cf456630a..9dd228b9c 100644
--- a/crates/ra_ide/src/references.rs
+++ b/crates/ra_ide/src/references.rs
@@ -130,13 +130,13 @@ fn find_name(
     opt_name: Option<ast::Name>,
 ) -> Option<RangeInfo<Definition>> {
     if let Some(name) = opt_name {
-        let def = classify_name(sema, &name)?.definition();
+        let def = classify_name(sema, &name)?.definition(sema.db)?;
         let range = name.syntax().text_range();
         return Some(RangeInfo::new(range, def));
     }
     let name_ref =
         sema.find_node_at_offset_with_descend::<ast::NameRef>(&syntax, position.offset)?;
-    let def = classify_name_ref(sema, &name_ref)?.definition();
+    let def = classify_name_ref(sema, &name_ref)?.definition(sema.db)?;
     let range = name_ref.syntax().text_range();
     Some(RangeInfo::new(range, def))
 }
diff --git a/crates/ra_ide/src/syntax_highlighting.rs b/crates/ra_ide/src/syntax_highlighting.rs
index 89efe71da..ec442bcd8 100644
--- a/crates/ra_ide/src/syntax_highlighting.rs
+++ b/crates/ra_ide/src/syntax_highlighting.rs
@@ -483,6 +483,7 @@ fn highlight_element(
             };
 
             match name_kind {
+                Some(NameClass::ExternCrate(_)) => HighlightTag::Module.into(),
                 Some(NameClass::Definition(def)) => {
                     highlight_name(db, def) | HighlightModifier::Definition
                 }
@@ -500,6 +501,7 @@ fn highlight_element(
             let name_ref = element.into_node().and_then(ast::NameRef::cast).unwrap();
             match classify_name_ref(sema, &name_ref) {
                 Some(name_kind) => match name_kind {
+                    NameRefClass::ExternCrate(_) => HighlightTag::Module.into(),
                     NameRefClass::Definition(def) => {
                         if let Definition::Local(local) = &def {
                             if let Some(name) = local.name(db) {
diff --git a/crates/ra_ide/src/syntax_highlighting/tests.rs b/crates/ra_ide/src/syntax_highlighting/tests.rs
index b9b358022..b8d60bdc6 100644
--- a/crates/ra_ide/src/syntax_highlighting/tests.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tests.rs
@@ -380,6 +380,23 @@ macro_rules! noop {
     );
 }
 
+#[test]
+fn test_extern_crate() {
+    check_highlighting(
+        r#"
+        //- /main.rs
+        extern crate std;
+        extern crate alloc as abc;
+        //- /std/lib.rs
+        pub struct S;
+        //- /alloc/lib.rs
+        pub struct A
+        "#,
+        expect_file!["crates/ra_ide/test_data/highlight_extern_crate.html"],
+        false,
+    );
+}
+
 /// Highlights the code given by the `ra_fixture` argument, renders the
 /// result as HTML, and compares it with the HTML file given as `snapshot`.
 /// Note that the `snapshot` file is overwritten by the rendered HTML.
diff --git a/crates/ra_ide/test_data/highlight_extern_crate.html b/crates/ra_ide/test_data/highlight_extern_crate.html
new file mode 100644
index 000000000..800d894c7
--- /dev/null
+++ b/crates/ra_ide/test_data/highlight_extern_crate.html
@@ -0,0 +1,40 @@
+
+<style>
+body                { margin: 0; }
+pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4em; }
+
+.lifetime           { color: #DFAF8F; font-style: italic; }
+.comment            { color: #7F9F7F; }
+.documentation      { color: #629755; }
+.injected           { opacity: 0.65 ; }
+.struct, .enum      { color: #7CB8BB; }
+.enum_variant       { color: #BDE0F3; }
+.string_literal     { color: #CC9393; }
+.field              { color: #94BFF3; }
+.function           { color: #93E0E3; }
+.function.unsafe    { color: #BC8383; }
+.operator.unsafe    { color: #BC8383; }
+.parameter          { color: #94BFF3; }
+.text               { color: #DCDCCC; }
+.type               { color: #7CB8BB; }
+.builtin_type       { color: #8CD0D3; }
+.type_param         { color: #DFAF8F; }
+.attribute          { color: #94BFF3; }
+.numeric_literal    { color: #BFEBBF; }
+.bool_literal       { color: #BFE6EB; }
+.macro              { color: #94BFF3; }
+.module             { color: #AFD8AF; }
+.value_param        { color: #DCDCCC; }
+.variable           { color: #DCDCCC; }
+.format_specifier   { color: #CC696B; }
+.mutable            { text-decoration: underline; }
+.escape_sequence    { color: #94BFF3; }
+.keyword            { color: #F0DFAF; font-weight: bold; }
+.keyword.unsafe     { color: #BC8383; font-weight: bold; }
+.control            { font-style: italic; }
+
+.unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
+</style>
+<pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module">std</span><span class="punctuation">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module">alloc</span> <span class="keyword">as</span> <span class="module">abc</span><span class="punctuation">;</span>
+</code></pre>
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